Regime‐Dependence of Nocturnal Nitrate Formation via N₂O₅ Hydrolysis and Its Implication for Mitigating Nitrate Pollution

Abstract

Abstract The heterogeneous hydrolysis of dinitrogen pentoxide (N 2 O 5 ) is an important pathway in nitrate formation; however, its formation rate and relative contribution to total particulate nitrate () are highly variable. Here we report that nocturnal formation via N 2 O 5 hydrolysis is dependent on the regime defined by the ratio of NO 2 to O 3 . Nocturnal formation via N 2 O 5 hydrolysis is suppressed in an O 3 ‐limited regime but enhanced in a NO 2 ‐limited regime. The results have crucial implications for effective control of nitrate pollution in the future. An exclusive decrease in NO 2 will decrease nocturnal formation in a NO 2 ‐limited regime but may be less effective or even increase nocturnal formation in an O 3 ‐limited regime.